Mail Server Setup . Please Help

now how to forge is my last hope . last 10 days all day and nights i have been trying to fix this issue . let me explain everything one by one
my server is dedicated server which is located in infolink datacenter new orleans -

IP is 64.251.1570 addditional IP is - 64.251.15.80

domain name - mybanglaspace.com

OS. FC-5 - with webmin and CP-Ispconfig

whenever i try to create Mx for mybanglaspace.com from ispconfig control panel it automaticaly add www with that . however i left hostname empty . though my mail server isnt appearing in dnsreport.com's report . then i have inserted MX record manualy which is --

IN MX 10 mail.mybanglaspace.com.
webmail IN CNAME mail
mail IN A 64.251.15.70

then i saw - in dnsreport.com its showing alright . and finaly my email arrived in gmail junk folder . but no sign in yahoo and hotmail . however i have asked my provider they provide me their smtp relay address which is mailout.infolink.com . now when i have sent email it gone to gmail inbox. good . solved i went to for rest after so many sleepless days and night . comeback in the next morning found . my users invitation mails and news letter all of them in mailquee ( postfix ) with this erorr message " delivery temporarily suspended: unknown mail transport error " 220 mail in qeuee . i thought it could be problem of my smtp relay they are not accepting mass mailing or mail via httpd ( [email protected] ) . however i i have removed smtp relay . and tried to send few invitations mail and mail from mysitefrom . now same thing same message" delivery temporarily suspended: unknown mail transport error " please help . i have tried stop postfix and using send mail but unable to start sendmail due to some reason send mail isnt working .

now i cant find any solutions for " delivery temporarily suspended: unknown mail transport error " . there is more than 400 mails in the qeuee

i have uninstall postfix and installed sendmail manualy . and test by sending mail from my website's invitation form . its working great . but problem is i cant see any old users mailbox from sendmail user mailbox . i can successfuly login to to webmail with old user name and password . but whenever send email it just doesnt go . its seems that send mail havnt intigrated with my server nor with ispconfig . any solutions .

as post fix was giving god damn eror which i couldnt fix for one week . all the mail was qeueeing up with error message " delivery temporarily suspended: unknown mail transport error " . trust me it made me crazy i had no choice . however now sendmail deliverying all of my mail correctly . mail even doesnt qeuee up for longer . just problem is i cant login with my old email addresses . is there anyway to fix it .

You can try to set the virtusertable path to /etc/mail/virtusertable and the local-host-names path to /etc/mail/local-host-names in ISPConfig (Management > Server > Settings > Email).
Change something afterwards in ISPConfig so that the new files get written.